我wǒ找zhǎo不bú到dào钥yào匙shi了liǎo。

I can't find the key.

把bǎ门mén钥yào匙shi给gěi我wǒ。

Give me the door key.

他tā用yòng钥yào匙shi开kāi了liǎo门mén。

He opened the door with the key.

我wǒ把bǎ钥yào匙shi忘wàng在zài车chē里lǐ了liǎo。

I left the keys inside the car.

邻lín居jū替tì我wǒ保bǎo管guǎn一yī把bǎ钥yào匙shi。

My neighbour keeps a spare key for me.